Part of the problem in discussing this is the assumption that there is a stable protocol: Japan’s modern Imperial institution is younger than the American Republic, and interactions with other heads of state have always been somewhat improvisational. Before the Meiji Restoration, the Emperor didn’t meet heads of state. For centuries, the Emperor basically met nobody who wasn’t a member of the court aristocracy or high officials of the shogunal state: there was no public protocol except for a vague tradition that required the Emperor be above the gaze of anyone, not to be looked down upon. That tradition was revived in the Imperial era, but it wasn’t much guidance in dealing with modern crowds, photography, diplomatic visits. Even Meiji’s coronation ceremony was an innovation, purged of Chinese elements and enhanced with Shinto rituals. (See Keene, ch. 18) The first head of state to visit was Hawaiian King Kalakaua, but he was actually preceeded by a visit from former President U.S. Grant who greeted the Emperor with handshakes. Every time an aristocrat or diplomat met the Emperor, protocol had to be negotiated in advance, and it shifted over time: when and how much to bow, whether handshakes would be permitted, whether foreign women could enter the Emperor’s presence with their diplomat husbands, etc. But this wasn’t yet the great age of state visits: that doesn’t come until the 20th century, and the rise of air travel.

Before the next America presidential visit with a Japanese emperor, though, WWII intervened: the Japanese Emperor was demoted from sacred and inviolable to the symbol of the State and of the unity of the people. More importantly, perhaps, Japan became a neo-colonial extension of American power for a time (when that time ends is a matter of debate, of course) so that Presidential courtesies like Nixon’s bow were harmless to American power. By the time of Clinton’s gesture, though, Japan’s economic power was a threat to American dominance (well, with the 90s recession, not really, but pundits had spent a good portion of the ’80s talking up the Japanese threat, and the impression stuck), and the Imperial transition of 1989 took away the American sense that the Emperor was someone who had been defeated and disarmed. Even Clinton’s gesture towards a bow was too much for some, apparently: the very concept of monarchy raised spectres of pre-Revolutionary attitudes, though bowing is not necessarily a subservient act when done between equals (or by a superior) in the Japanese tradition.

Obama’s bow is a very formal one — formality and hierarchy are two different things — and in the context of a handshake. It doesn’t change the nature of the US-Japan relationship as much as the election of Japan’s new non-LDP PM, as much as the rising nationalistic culture, as much as the ongoing shifts in the economic relationship between two of the largest — and most obviously struggling — economies in the world.